The returned string belongs to 'message' and as such, should not be
modified by the caller and will only be valid for as long as the
message is valid, (which is until the query from which it derived
is destroyed).
This function will not return NULL since Notmuch ensures that every
message has a unique message ID, (Notmuch will generate an ID for a
message if the original file does not contain one).
Get the message ID of 'message'.
The returned string belongs to 'message' and as such, should not be modified by the caller and will only be valid for as long as the message is valid, (which is until the query from which it derived is destroyed).
This function will not return NULL since Notmuch ensures that every message has a unique message ID, (Notmuch will generate an ID for a message if the original file does not contain one).